April 16, 2012

Asian Glaciers Bulk Up, Confusing Researchers

Bucking the global trend, some Asian glaciers on Karakoram´s mountains are getting thicker, according to researchers.

A French team used satellite images to show that the Karakoram glaciers, located west of the Himalayan region, were putting on mass.

It is still unclear why these glaciers are gaining weight. The glaciers in other parts of the Himalayas are following the global trend and losing mass.

The glaciers in this region remain poorly studied, despite the fact they provide water for more than a billion people.

A report from the Intergovernmental Panel on Climate Change (IPCC) in 2007 claimed most of the ice in this region could disappear by the year 2035. Since then, this glacier has been a hot topic of debate amongst researchers and scientists.

The Karakoram range is technically a separate range from the Himalayas and includes the world´s second-highest peak, K2.

The French team responsible for the new research conducted the study in response to a call for more thorough observations of this inaccessible region.

The team of scientists, from the National Centre for Scientific Research (CNRS) and the University of Grenoble, compared two models of land surface elevation taken from satellites in 1999 and 2008. They reported their findings in Nature Geoscience.

This isn´t the first time this method of comparing satellite models has been used, however.

“It´s not been used more because these elevation models are quite difficult to acquire – you need clear sky conditions and reduced snow cover,” said lead researcher Julie Gardelle, speaking to BBC News reporter Richard Black.

When all the calculations were complete, the team found the mass of the glaciers had increased marginally in between 1999 and 2008. Individual glaciers, however, showed wide variations in their size.

It is not yet clear why these glaciers are growing, if only marginally so, while other glaciers are losing their mass. Other studies have shown climate change in other parts of the world can cause extra precipitation in colder regions. If this precipitation falls in areas cold enough, it will be added to the existing mass of ice.

“We don´t really know the reason,” Ms Gardelle told Black. “Right now we believe that it could be due to a very specific regional climate over Karakoram because there have been meteorological measurements showing increased winter precipitation; but that´s just a guess at this stage.”

Other parts of the wider Himalayas-Hindu Kush region are not sharing in this growth trend, which is startling considering these glaciers provide fresh water for an estimated 1.3 billion people living in the river basins below.

The Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) provided data late last year showing the rate of ice loss across 10 regularly studied glaciers has doubled since the 1980s.

The ICIMOD also noted how sparse the data from this region can be. Out of the 54,000 glaciers in the region, only 10 were studied regularly. According to measurements taken by the GRACE satellite mission, which can detect variations in the Earth´s gravitational pull, there has been a net loss of mass across the entire region of glaciers. Graham Cogley, a scientist from Trent University in Ontario, Canada first publicly the IPCC´s 2035 figure. He seems less than optimistic when it comes to determining the how much mass has been lost, saying it “will keep glaciologists busy for some time”.